1. Field of the Invention
This invention generally relates to an ink-jet printer of the type for charging ink droplets selectively and deflecting charged ink droplets, and, in particular, to a multi-nozzle ink-jet printer including a plurality of ink ejecting ports.
2. Description of the Prior Art
An ink-jet printer is well known in the art and there are several types of ink-jet printers. One of the types which is widely used is of the type in which ink droplets are ejected out of an ink nozzle, selectively charged varyingly in accordance with an image signal and deflected by a pair of deflecting electrodes between which a deflecting electric field is formed. This type of ink-jet printer may be provided with a multi-nozzle head including a plurality of ink-discharging nozzles arranged in the form of a linear array. Such a multi-nozzle ink-jet printer is advantageous because a plurality of ink droplets are ejected at the same time in parallel so that printing speed can be increased.
However, since the diameter of an ink nozzle from which ink droplets are ejected is relatively small in size, the ink ejecting performance could differ from one nozzle to another significantly. Thus, ink droplets ejected from different nozzles could differ in velocity, which is disadvantageous because there is only obtained a printed image with distortion. Accordingly, it is important that the velocity of flying ink droplet is measured and controlled such that the ink droplets flying in parallel should have substantially the same velocity so as to enhance the quality of printed image.